Halogen ion modified Ag NPs for ultrasensitive SERS detection of nitroaromatic explosives.

Trace explosive detection has become one of the hottest topics in scientific communities because homeland security is one of the top priorities for countries all around the world. In this work, Ag NPs prepared with different reducing reagents were modified with various halogen ions for the SERS detection of nitroaromatic explosives (2,4-DNT and 2,4,6-TNT). It was proposed that halogen ions probably replaced the surface adsorbates on Ag NPs, <i>i.e.</i>, citrate ions, and gave surface access to target analytes, which in turn enhanced the SERS signal. The LOD values for TNT and 2,4-DNT were found to be only 2 femtomoles. Given its facile and the highly sensitive process, the method that we demonstrated can serve as a promising analytical technology for the ultrasensitive SERS detection of nitroaromatic explosives.